Associated HI in Absorbers at High Redshift
| dc.creator | Vermeulen, R. C. | |
| dc.date | 2000-12-15 | |
| dc.date.accessioned | 2026-07-07T01:57:03Z | |
| dc.date.available | 2026-07-07T01:57:03Z | |
| dc.description | WSRT observations have provided a first inventory of the incidence of HI 21 cm line absorption associated with AGN at redshifts up to z=1.0. There is a large range in line depths, from tau=0.44 to tau less than 0.001, and a substantial variety of line profiles, from Gaussians of less than ten km/s to more typically a few hundred km/s, as well as irregular and multi-peaked absorption, sometimes spanning many hundreds of km/s. The chance to detect appreciable HI absorption is greatest in the most compact radio sources, GPSs and CSOs, where it can occur in circumnuclear ``disks'' or ``tori'', as well as in gas enveloping jets and hot spots; inferred densities range at least between 10 per cubic cm and 10000 per cubic cm. But HI absorption occurs also in some CSSs, perhaps associated with jet-cloud interaction regions, and in quasars with a large optical reddening. VLBI observations at the unusual UHF frequencies of redshifted HI 21 cm can give unique ``sight''lines into the physics and evolution of young radio sources and their inner galactic medium. | |
| dc.description | 4 pages, 2 postscript figures, LaTeX, uses paspiau199.sty. to appear in "The Universe at Low Radio Frequencies", IAU Symposium 199, ASP Conference Series, V.K. Kapahi & A.P. Rao (eds.) | |
| dc.identifier | https://arxiv.org/abs/astro-ph/0012352 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/0012352 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/2235 | |
| dc.subject | Astrophysics | |
| dc.title | Associated HI in Absorbers at High Redshift | |
| dc.type | text |